Sewing machine for straight or zigzag sewing



Sept. 23, 1969 A. MORO SEWING MACHINE FOR STRAIGHT OR ZIGZAG SEWING 2Sheets-Sheet 1 Filed Feb.

F/GSD Attorneys I Sept. 23, 1969 MORO 3,468,270

SEWING MACHINE FOR STRAIGHT 0R ZIGZAG SEWING Filed Feb. 27, 1967 2SheetsSheet 2 I nvenlor fl/vro/v/a Maea Bykwy JMAJ Attorneys UnitedStates Patent ice 3,468,270 SEWING MACHINE FOR STRAIGHT 0R ZIGZAG SEWINGAntonio Moro, Milan, Italy, assignor to Soc. per Azioni FratelliBorletti. Milan. Italy, an Italian company Filed Feb. 27, 1967, Ser. No.618,830 Claims priority, application Italy, Mar. 1, 1966, 15,048/ 66Int. Cl. Db 3/02 US. Cl. 112158 3 Claims ABSTRACT OF THE DISCLOSURE Asewing machine for domestic use, of the type adapted to produce straightzigzag stitching and having an oscillating pendulum, a needle barslidably mounted in the pendulum, a cam for imparting the oscillation, atransmission rod associated at one end with the pendulum and at theother end with an oscillating lever driven by the cam to reciprocate thetransmission rod, is improved in two respects:

(1) An operating knob and an eccentric pin fast therewith shift the axisof oscillation of the lever so as to stitch to the right or to the leftor on center or in any other intermediate position; and

(2) Another operating knob and eccentric pin fast therewith transverselyshift the transmission rod so that its driven end moves toward or awayfrom the axis of the oscillating lever thereby to change the amplitudeof pendulum oscillation.

The object of the present invention is a sewing machine of the typeadapted to carry out straight or zigzag stitching, this machine beingfor domestic use and cheap to make.

In the present state of the art, sewing machines which carry outstraight or zigzag sewing at choice and enable the start of thestitching to be fixed in the centre, on the right or on the left of theworking range of the needle are known and widely distributed. There aremany kinds of devices which perform this function and the improvementswhich are being studied today aim essentially at making the machinesimpler and more economical without, however, foregoing a high level offunctionality or the widest sewing possibilities of the machine.

The aim of the present invention is precisely to produce a machinewhich, in addition to normal straight sewing, will also carry out zigzagsewing by the use of mechanisms which are simply constructed and easy toapply and also of control elements adapted to be actuated from outsidethe machine and which are practical to use and can be usedinstantaneously.

The sewing machine according to the present invention is more preciselyof the type comprising a needle bar slidable in an oscillating pendulum,a cam controlling the oscillation and a transmission rod associateddirectly at one end with the said pendulum and co-operating indirectlyat the other end with the said cam to transmit the oscillation producedby the latter to the said pendulum; the machine is characterisedsubstantially in that an oscillating lever with an arm having .an actionof adjustable amplitude is interposed between the profile of the saidcam and that end of the transmission rod which co-operates with the cam.

3,468,270 Patented Sept. 23, 1969 Preferably, the said oscillating leveris pivoted at one end at a substantially fixed point of the machine andis kept in contact at the other end with the cam controlling theoscillation, the end of the said transmission rod being kept in contactin turn with the said oscillating lever, with the possibility ofdisplacement along the same.

The following description, however, is intended to explain the structureand operation of the invention better on the basis of the accompanyingdrawings, which relate to a preferred constructional form and in which:

FIG. 1 is a longitudinal section of the arm of the machine, in thevertical plane of the device according to the invention;

FIG. 2 is a diagrammatic plan view of the said device;

FIG. 3a shows in section the knob and eccentric pin for controlling thestarting position of the stitching;

FIG. 3b is a front view of the said knob;

FIGS. 4a, 4b and 4c are a longitudinal section and a cross-section ofthe assembly of the knob adjusting the amplitude of the zigzag and afront view of the said knob;

FIGS. 5:: and 5b show, partly in section, the control for the engagementand disengagement of the zigzag device, in its two operative positions;

FIG. 6 shows a detail of the mounting of the gear with the cam and whichis controlled by the gear fixed to the main shaft;

FIGS. 7a, 7b and show various working positions of the lever armcontrolling the zigzag.

The shaft 1 (FIGS. 1, 2) controls in known manner, in the front part 2of the machine, the vertical movement of the needle bar and the threadtake-up lever, and, in the rear part 3, the elements which actuate theshuttle or the rotating hook, according to the type of machine, and thematerial feeding device, all of which are of known type; mounted on theshaft 1 is the helical gear 4 meshing with the gear 5 with atransmission ratio of 2:1, so that the gear 5 makes one revolution forevery two revolutions of the gear 4. The gear 5 is mounted rotatably onthe pin or pivot 6 (FIG. 6) projecting from a stationary body 7 having ahole normal to the axis of the pin 6; by means of the said hole, thebody 7 is mounted on the vertical pin 8 fixed to the frame and isclamped by means of the screw 9 after the optimum position for meshingof the gears 4 and 5 has been found.

The cam 10 of the three-lobed form is integral with the gear 5 andtherefore performs one revolution for every two revolutions of the mainshaft 1.

A pin or pivot 11 (FIG. 3a) parallel to the pin 6 is mounted rotatablyin the hole 13 in the wall 14 of the frame arm of the machine; insidethe machine, the pin 11 is extended in a pin 12 having its axiseccentric with respect to the axis of the pin 11.

Mounted for oscillation on the eccentric pin 12 is the lever arm 15,which bears on the surface of the cam 10 through a convex zone 16(FIG. 1) shaped with a small radius and parallel to the pin 12. Duringthe rotation of the cam, the lever arm 15 performs angular oscillationsabout the pin 12 (see FIG. 7), passing alternately into the positions 17and 18, with an angular movement corresponding to the difference betweenthe angle a (FIG. 7a) and the angle B (FIG. 7b).

Under these conditions, the rod 19 (FIG. 1), which is pivoted at one endto the pendulum 20 carrying the needle bar and oscillating through themedium of the hinge 20', and which keeps its other pointed end 22incontact with the surface 23 of the lever arm 15 through the action of aspring 21, will be subjected to an axial displacement, corresponding tothe oscillation of the lever arm 15, in the directions of the arrows 24(FIG. 1). This displacement or movement is of zero value when the point22 is at the top, in a position coinciding substantially with the axisof the pin 12 (FIG. 7b), and has a maximum value when the point 22 islocated almost in correspondence with the point of contact between thezone 16 and the cam 10 (FIG. 70). The movements of the rod 19 aretransferred proportionately to the needle bar, which latter will performcorresponding lateral excursions, with an amplitude from zero to amaximum, for the formation of the zigzag stitch.

If the end 22 of the rod 19 remains at the top, in correspondence withthe axis of the pin 12, the needle does not oscillate transversely andthe stitching is straight.

It is possible to rotate the pin 11 by means of the knob fast therewithand obtain a shifting of the eccentric pin 12, for example to the right(FIG. 7a); in this way, there is also obtained a shifting of the needleto the right and, as long as the point 22 remains in coincidence withthe axis of the eccentric 12, straight stitching will be obtained, alland always on the right of the working range. As has been said above, byshifting the point 22 along the surface 23, transverse movement of theneedle for the formation of the zigzag, with increasing amplitude, isobtained; the characteristic of the zigzag stitches obtained in this wayis that they always start from a position on the right, or on theright-hand margin of the working range, whatever their amplitude.

In symmetrical fashion, if the pin 12 is shifted completely to the left,into the position shown in FIG. 7c, straight stitching on the left andzigzag stitching in which the stitches always start from the left-handmargin of the working range will be obtained. Similarly, forintermediate positions of the pin 12, intermediate sewing positions willbe obtained.

The extreme simplicity of construction and operation of the deviceaccording to the invention is obvious, this being achieved by insertinga simple lever arm 15 between the control cam 10 and the transmissionrod 19 connected to the pendulum of the needle bar.

The shifting of the point 22 of the rod 19 along the surface 23 iscontrolled by means of the knob 26 (FIGS. 2 and 4a), which is fast withthe pin 27 mounted rotata'bly in the bush 27 formed by the wall 14.

Keyed on the pin 27 at that end which is remote from the knob 26 andinside the wall 14 is the arm 28 (FIG. 4b) to which the pivot 29 isfixed eccentrically with respect to the axis of the pin 27. Mounted onthe pivot 29 is one end of the link 30 carrying at the other end thepivot 31 (FIG. 4a) engaging in a hole in the rod 19. Upon turning theknob 26, the pivot 29 performs an excursion in the vertical directioncarrying the link 30, and therefore the rod 19, with it. The screws 28',which are adjustable in suitable seats at the ends of the arm 28, havean arresting function, so that the knob 26 can be made to turn onlythrough a given angle corresponding to the maxi-mum excursion of thepoint 22, substantially between the axis of the pin 12 and the point ofcontact between the surface 16 and the cam 10.

The end 32 of the rod 19 is pivoted to the pendulum 20 (FIG. 1) at 32 bymeans of a pin 33 (FIG. 2) provided with an eccentric and which can beclamped by means of the set screw 34; this connection enables thependulum of the needle bar to be set in the correct position withrespect to the cam 10 by simply turning the pin 33 until the needle iscentered over the hole in the needle plate and then locking it by meansof the set screw 34. As has been said, the spring 21 holds the point 22of the rod 19 in contact with the surface 23 of the lever arm 15, whilea spring 35 holds the free end of the lever 15 in contact with the cam10.

When the machine is to carry out only straight stitching, it is usefulto exclude operation of the zigzag stitching device completely, so asnot to subject the cam 10 to working unnecessarily.

To this end, the lever 36 (FIGURES 5a, b) is provided, this beingpivoted on the end 37 of the pin 6 and moreover having a short arm 38terminating in a flat transverse edge; when the lever 36 is in therighthand position 39 illustrated in FIG. 5a, the lever 15 can oscillatefreely, controlled by the cam 10, so as to produce the zigzag stitch. Onthe other hand, when the lever 36 is shifted into the left-hand positionindicated in FIG. 5b, the end of the arm 38 is disposed so that the stud38 fast with the lever 15 bears on the said end so as to hold the lever15, and more exactly the zone 16, out of engagement with the cam 10. Thelatter then rotates idly, avoiding unnecessary wear, and the zigzagstitching device remains inoperative.

It is then possible to make straight stitching or seams which arecentral, on the right or on the left, according to the angular positionof the knob 25, it being possible to check this position by bringing oneof the marks 40 into line with the fixed index 41 (FIG. 3b)

The amplitude of the zigzag, on the other hand, can be read on thegraduated scale 42 (FIG. 40) on the knob 26 with respect to the fixedindex 43.

With the device according to the present invention, which is ofextremely simple construction and assembled inside the arm of themachine, and by operating separately or in combination the knobs 25 and26 and the lever 36, it is possible to obtain with the maximum ease andsimplicity, at will and according to the ability of the user, straightstitching on the right, on the left or in the centre; zigzag stitchingof an amplitude adjustable from zero to a maximum, with its origin inthe centre, on the right or on the left; invisible stitching,buttonholes, various ornamental stitches, embroidery, mending,attachment of buttons and other needlework.

It is to be understood, however, that other practical constructionalforms of the present invention may be different from that describedwithout thereby departing from the scope of the said invention.

What I claim is:

1. In a sewing machine for domestic use, of the type adapted to producestraight or zigzag stitching and comprising an oscillating pendulum, aneedle bar slidably mounted in said oscillating pendulum, a cam forimparting said oscillation, a transmission rod associated at a first enddirectly with said pendulum, and an oscillating lever cooperating on oneside with said cam and on the other side with the second end of saidtransmission rod for transmitting the oscillation imparted by the cam tothe needle bar; the improvement comprising a knob and an eccentric pinfast therewith, the knob being accessible to be operated from outsidethe machine, said oscillating lever being pivotally mounted on saideccentric pin, the operation of said knob and eccentric pin providing adisplacement of the axis of oscillation of said lever in a directionsubstantially parallel to the direction of action of said cam.

2. Apparatus as claimed in claim 1, and a second knob and an eccentricpin fast therewith, said second knob being accessible to the operatorfrom outside the machine, and means interconnecting said eccentric pinand said transmission rod to shift the transmission rod laterally of thedirection of oscillation of the transmission rod and along said leverthereby to change the distance between said second end of thetransmission rod and said axis of oscillation of said lever thereby tochange the amplitude of reciprocation of said transmission rod.

3. In a sewing machine for domestic use, of the type adapted to producestraight or zigzag stitching and comprising an oscillating pendulum, aneedle bar slidably mounted in said oscillating pendulum, a cam forimparting said oscillation, a transmission rod associated at a first enddirectly with said pendulum, and an oscillating lever cooperating on oneside with said cam and on the other side with the second end of saidtransmission rod for transmitting the oscillation imparted by the cam tothe needle bar; the improvement comprising a knob and an eccentric pinfast therewith, said knob being accessible to the operator from outsidethe machine, and means interconnecting said eccentric pin and saidtransmission rod to shift the transmission rod laterally of thedirection of the transmission rod and the axis of oscillation of saidlever thereby to change the amplitude of reciprocation of saidtransmission rod.

References Cited UNITED STATES PATENTS of oscillation of thetransmission rod and along said lever 10 RICHARD J. SCANLAN, JR.,Primary Examiner thereby to change the distance between said second end

